Method of forming crimped artificial filaments



July 14,1959

Filed NOV. 16, 1955 FILAMENTS United States Patent METHOD OF FORMINGCRIlVIPED ARTIFICIAL FILAMENTS Richard H. Braunlich, West Chester, Pa.,assignor to American Viscose Corporation, Philadelphia, Pa, acorporation of Delaware Application November 16, 1955, Serial No.547,180

8 Claims. (Cl. 18-54) The invention relates to the manufacture ofartificial filaments, and particularly to the production of crimpedartificial filaments.

In forming artificial filaments, as for example from viscose material,various methods have been utilized to impart a desired crimp to thefinished yarns. Some of these prior methods have relied upon mechanicaldeformation of the filaments, as for example by passing the same betweena pair of meshing gears, while other known methods rely upon a pile upof filaments in the regenerating bath, as shown for example in Figure 4of the United States Patent 2,625,461 to Richter, In, et al. Inaccordance with the present invention, a marked departure is made fromthe conventional crimping methods by inducing strains in the cellulosestructure of the filaments as they emerge from the coagulating acid baththereby causing the filaments to crimp. During the coagulating stage,little or no regeneration of the filaments takes place and thus thefilaments emerge therefrom with a large percentage (50% or more) of thecellulose in the tow remaining in the form of cellulose xanthate. Thetow at this stage will maintain a xanthate form for a considerablelength of time when kept in a wet condition, and it is during this timethat it is subjected to an uneven application of heat which producesuneven regeneration and a resulting crirnped finished yarn.

It is a primary object of the present invention to provide a generallynew or improved and more satisfactory method for producing crimped yarn.

Another object is the provision of a method of inducing strains into atow of partially formed filaments to impart a crimping thereof.

Still another object is to provide a method of crimping a tow offilaments by the uneven regeneration thereof.

These and other objects and advantages of the invention will be apparentfrom the following description and accompanying drawing in which:

Figure 1 is a diagrammatic side view of apparatus suitable forpracticing the present invention and serves to illustrate various stagesthrough which the tow passes during its production;

Figure 2 is a front view of one form of godet for applying heated fluidto the tow of filaments; and

Figure 3 is a view similar to Figure 2 illustrating a modified godet.

In general, the invention is directed to the crimping of filaments byheating a tow of partially formed filaments at spaced locations alongits length as it emerges from the coagulating bath. Upon leaving thecoagulating bath, the greater portion of the cellulose in the tow is inthe xanth ate form, thus the heated areas of the tow are regeneratedmore rapidly than the remaining portions thereby inducing strains intothe tow which produce the resulting crimp in the finished yarn. Theuneven heat application to the tow is preferably accomplished by passingthe tow spirally about a godet having a plurality of closely spacedradially extending heated fins, or a godet having a slotted peripheralwall through which steam or other heated fluid can flow and contact theadjacent tow areas. Preferably, but not necessarily, the method of thepresent invention can be incorporated into the two step spinning"process described in the United States Patent 2,625,461 to Richter, Ir.,et a1.

With reference to Figure l of the drawing, and as more specificallydescribed in the above-noted patent to Richter, Jr., et al., the tow ofartificial filaments 9 is formed by spinning a viscose material throughthe spinneret 11 and into the coagulating bath 13 which comprises, forexample, an aqueous solution of sodium sulfate and an acid sodiumphosphate, and which may also include a phosphoric acid. The bundle ortow of cellulose xanthate filaments thus formed are passed over a guide15 and over the godets 17 and 19, between which are provided a pair ofstaggered guides 21 and 23 for stripping the excess coagulating bathfrom the tow. In passing from the godets 17 and 19, the filaments arestretched to the desired extent as more particularly described in theabove-noted patent. Upon leaving the godet 19, the tow of filaments passinto the regenerating bath 25, which at the start of operationcomprises, for example, an aqueous solution of sulphuric acid,phosphoric acid, and sodium sulfate. From the regenerating bath the tow9 passes over a guide 27 and between the guides 29 and 31 which removethe excess regenerating bath before the tow is received by the godet 33.After passing over the godet 33, the filaments may then be disulfided,bleached, washed, treated with a finish, dried, and collected in acontinuous and conventional manner.

When leaving the coagulating bath, approximately 50% or more of thecellulose in the tow remains in the xanthate form and maintains thisform for a considerable period of time when kept in a wet condition. Inaccordance with the present invention, the method described in theabove-cited patent is modified by producing an uneven regeneration ofthe cellulose in the tow as it emerges from the coagulating bath, thussetting up strains in the cellulose structure and providing a crimpingof the finished yarn. Uneven regeneration is produced, preferably, byheating spaced areas along the length of the tow to a temperaturepreferably in the range of 50 C. to C. and thus the godet 17 may beprovided with radial fins capable of being heated or with slots fordischarging heated fluid onto the tow as it passes thereof. A heatedfinned godet having a construction as shown for example in the UnitedStates Patent 2,620,258 to McLellan or a slotted godet as shown inFigures 2 and 3 is considered to be satisfactory.

As shown in Figure 2, the godet is of hollow construction and includes acylindrical wall 35 secured at one end to the end wall 37, which is ofgreater diameter than the wall 35, and is closed at its opposite endwith a suitable structure not shown. A tubular shaft 39 is rigidlysecured at one end to the wall 37 and is adapted to be rotated in theconventional manner for turning the godet about its axis. Extending intothe shaft 39 is an inlet conduit 41 through which hot fluids, such asair, steam, or a regenerating acid, is conveyed into the hollow interiorof the godet. The fluid received in the godet is discharged therefromand onto the tow at spaced points along its length through the elongatedslots 43 which are disposed longitudinally of the cylindrical wall 35and approximately parallel to the godet axis. From the godet structuredescribed, it is evident that the hot fluids will cause the selectedspaced areas of the tow to be regenerated more rapidly than theremaining area thereby setting up strains in the cellulose structureswhich provide the desired crimp in the filaments themselves.

The modified godet shown in Figure 3 is generally similar to that shownin Figure 2 and includes a cylindrical wall 45 connected to an end wall47 which is similar to the wall 37 heretofore described. A shaft 49,fixed to the wall 47, imparts a rotary movement to the godet. As in thestructure shown in Figure 2, a conduit 51 supplies heated fiuid to thehollow interior of the godet from which it is discharged through thelongitudinally spaced series of peripheral slots 53 and 55. The slots 53and 55 extend longitudinally of the cylindrical wall 45 and aresubstantially parallel to the godet axis. However, in this construction,it will be noted that the peripheral slots 53 are in staggeredrelationship relative to the slots 55 in the adjacent series. In thismanner, the areas of the tow 9 subjected to the heating fluid passingthrough the slots 53 will lie intermediate those areas heated by thefluid passing through the slots 55.

It will be of course understood that the godet constructions shown inFigures 2 and 3 are merely given by way of example, and that the fluiddischarging slots may be disposed at a diagonal or in any other suitableposition if desired.

After passing over the godet 17, the unevenly regenerated cellulose towis passed over the godet 19 and then undergoes the usual and knownproduction stages as described above in relationship to the method setforth in the Richter, Jr., et al. patent. The method of crimpingartificial filaments as described above can be carried out with only aslight modification of the Richter, Jr., et al. method, and does notnecessitate the installation of any complex and expensive equipment.Furthermore, the crimping of the filaments by setting up strains in thecellulose structure permits any desired crimping pattern to be appliedwhich was not heretofore possible with the method shown in Figure 4 ofthe Richter, In, et al. patent, and eliminates any risk of damaging thefilaments as is possible when the filaments are crimped by passing thesame through a pair of meshing gears.

It is seen from the above description that the objects of the inventionare well fulfilled by the method and apparatus described. Thedescription is intended to be illustrative only and it is to beunderstood that changes and variations may be made without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

I claim:

1. The method of forming crimped artificial filaments including thesteps of extruding a viscose solution into a coagulating bath to form acontinuous tow of filaments,

4 and regenerating the coagulated tow of filaments at longitudinallyspaced intervals therealong to induce strains and a resulting crimpingthereof.

2. The method of forming artificial filaments including the steps ofextruding a viscose solution into a coagulating bath to form a tow offilaments, and rapidly regenerating spaced areas of the tow along itslength immediately after it is withdrawn from the coagulating bath toinduce strains and a resulting crimping thereof.

3. The method of forming crimped artificial filaments including thesteps of extruding a viscose solution into an aqueous coagulating bathto form a tow of filaments, heating spaced areas along the tow length toproduce uneven regeneratlon, and passing the tow through an aqueousregenerating bath to complete regeneration thereof.

4. A method as defined in claim 3 wherein heating of said tow iseffected by hot fluid.

5. A method as defined in claim 4 wherein said fluid is a celluloseregenerating acid.

6. A method as described in claim 3 wherein heating of said tow iseffected to a temperature ranging from C. to C.

7. A method of forming crimped artificial filaments including the stepsof extruding a viscose solution into a coagulating bath to form a tow offilaments, straining the cellulose structure of the coagulated tow offilaments at spaced points along the tow length, and subsequentlypassing said tow of filaments through a regenerating bath.

8. A method of forming crimped artificial filaments inluding the stepsof regenerating a tow of viscose filaments in the cellulose xanthateform to a degree varying intermittently along its length, and passingthe tow of filaments through an aqueous bath to complete theregeneration thereof.

References Cited in the file of this patent UNITED STATES PATENTS2,244,281 Alibert June 3, 1941 2,413,123 Underwood Dec. 24, 19462,447,131 McDermott Aug. 17, 1948 2,491,937 Schlosser Dec. 20, 19492,582,639 Ljungberg Jan. 15, 1952 2,620,258 McLellan Dec. 2, 19522,625,461 Richter Ian, 13, 1953 2,774,423 Griset Dec. 18, 1956

3. THE METHOD OF FORMING CRIMPED ARTIFICIAL FILAMENTS INCLUDING THE STEPS OF EXTRUDING A VISCOSE SOLUTION INTO AN AQUEOUS COAGULATING BATH TO FORM A TOW OF FILAMENTS, HEATING SPACED AREAS ALONG THE TOW LENGTH TO PRODUCE UNEVEN REGENERATION, AND PASSING THE TOW THROUGH AN AQUEOUS REGENERATING BATH TO COMPLETE REGENERATION THEREOF. 